The present invention relates to information-providing systems based on radio communications satellite broadcasting.
As set forth in Japanese Application Patent Laid-Open Publication No. Hei-170628 (1998), one typical method of transmitting information to mobile bodies using a broadcasting system consists of the following steps:
Segmenting the information transmission range into smaller areas
Assigning an identification code to each area
Linking a communications channel to each identification code
Determining for each area the information to be transmitted
Transmitting information using the corresponding channel
Reading at the receiving side the identification code for the area corresponding to the current location of the mobile body
Selecting the appropriate receiving channel
Receiving the information linked to the corresponding area
Also, as set forth in Japanese Application Patent Laid-Open Publication No. Hei-259398 (1997), another typical method of transmission consists of the following steps:
Segmenting the information transmission range into smaller areas
Assigning an identification code to each area
Determining for each area the information to be transmitted
Transmitting information with each area identification code added to the information
Reading at the receiving side the identification code for the area corresponding to the current location of the mobile body
Selecting from all received information only the information matching the added identification code
The means of transmitting road regulation information to the drivers on the road in order to urge them to drive safely, refers to road signs or road markings. Drivers visually recognize the road signs or road markings located outside the respective vehicles. For such a road sign detection system as disclosed in Japanese Application Patent Laid-Open Publication No. Hei-269921 (1997), radio signal transmitters are installed at each component of road infrastructure, such as a road sign, and regulation information is transmitted to each driver via a carborne receiver to notify alarms and the like to the driver. The xe2x80x9cSTRIVE2: Development of an ITS Service Simulatorxe2x80x9d in IPS Research Reports Vol. 99, No. ITS-2, pp. 45-52 (IPS: Information Processing Society of Japan) reports that when viewing a road sign from a moving vehicle, it is difficult for the driver to momentarily confirm or judge details of the information contained in the road sign, such as time limits and the trafficability specified for each vehicle type, and that when the vehicle is driven at night or the driver""s vision is blocked by a large vehicle, the driver is prone to overlook the traffic sign or signal. In order to solve these problems, therefore, the report mentioned above suggests implementing a driver support function that automatically displays only the necessary sign information at the carborne information terminal according to the particular type of vehicle or the time zone applied.